package test01;

import java.math.BigInteger;
import java.util.Scanner;

public class Test_1042 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()){
            int n = sc.nextInt();
            BigInteger bigInteger = BigInteger.valueOf(1);
            for (int k = 1; k <= n; k++) {
                bigInteger = bigInteger.multiply(BigInteger.valueOf(k));
            }
            System.out.println(bigInteger);
        }

    }
}



